“That's all the motorcycle is, a system of concepts worked out in steel. There's no part in it, no shape in it, that is not out of someone's mind”

Source: Zen and the Art of Motorcycle Maintenance (1974), Ch. 8
Context: I've noticed that people who have never worked with steel have trouble seeing this—that the motorcycle is primarily a mental phenomenon. They associate metal with given shapes—pipes, rods, girders, tools, parts—all of them fixed and inviolable, and think of it as primarily physical. But a person who does machining or foundry work or forge work or welding sees "steel" as having no shape at all. Steel can be any shape you want if you are skilled enough, and any shape but the one you want if you are not.

"Model's Web rants pined for love" in Daily News (29 June 2009)

Source: The Romantic Generation (1995), Ch. 1 : Music and Sound

Source: Kingdom of Fear: Loathsome Secrets of a Star-Crossed Child in the Final Days of the American Century

Two Miles and Hour
The Red Light District

Dion Fortune, The Mystical Qabalah

Sometimes attributed to Augustine, but is from Phyllis McGinley https://en.wikipedia.org/wiki/Phyllis_McGinley, The Province of the Heart, "The Honor of Being a Woman" (1959).
Misattributed

Out of Control: The New Biology of Machines, Social Systems and the Economic World (1995)

Source: 1930s, Principles of topological psychology, 1936, p. viii.